This disclosure is generally directed to layered imaging members, photoreceptors, photoconductors, and the like that can be selected for a number of systems, such as copiers and printers, especially xerographic copiers and printers inclusive of printers that generate color xerographic documents, and which printers can be selected for the office environment, and for production and commercial printing uses. More specifically, the present disclosure is directed to multilayered drums, or flexible belt imaging members or devices comprised of a supporting medium like a substrate, an optional ground plane layer, an optional hole blocking layer, a photogenerating layer, and a charge transport layer, including at least one or a plurality of charge transport layers, and wherein at least one charge transport layer is, for example, from 1 to about 7, from 1 to about 3, and one; and more specifically, a first charge transport layer and a second charge transport layer, and where a poly(imide-carbonate) polymer, especially a copolymer thereof, and a fluorinated material, such as a polytetrafluoroethylene (PTFE) are present in the charge transport layer that is in contact with the photogenerating layer. The poly(imide-carbonate) polymer and polytetrafluoroethylene containing photoconductors possess, in embodiments, excellent wear characteristics, and where the poly(imide-carbonate) polymer functions, for example, as a charge transport layer (CTL) first or second resin binder, and the second or first binder is, for example, a fluorinated polymer, such as polytetrafluoroethylene or in embodiments a polycarbonate and mixtures of polycarbonates and polytetrafluoroethylenes.
The photoconductors disclosed herein possess it is believed a number of advantages such as, in embodiments, the minimal wearing of the charge transport layer or layers especially in xerographic copying and printing systems; the minimization or substantial elimination of undesirable ghosting on developed images, such as xerographic images, including decreased ghosting at various relative humidities; excellent cyclic and stable electrical properties; minimal charge deficient spots (CDS); compatibility with the photogenerating and charge transport resin binders; extended xerographic biased charge roller wear characteristics, and acceptable lateral charge migration (LCM) characteristics, such as for example, excellent LCM resistance.
Yet more specifically, an advantage of the photoconductors in embodiments of the present disclosure is that the wear rates when selecting for the charge transport layer a fluorinated polymer, like PTFE and a poly(imide-carbonate) polymer mixture was from about 15 to about 20 nanometers/kilocycle, about 50 to about 70 percent of that of a PTFE charge transport layer (CTL) (with no poly(imide-carbonate) polymer, a wear rate of about 30 nanometers/kilocycle). The wear rate is measured using an in-house known wear fixture as illustrated herein.
Ghosting refers, for example, to when a photoconductor is selectively exposed to positive charges in a number of xerographic print engines, and where some of the positive charges enter the photoconductor and manifest themselves as a latent image in the subsequent printing cycles. This print defect can cause a change in the lightness of the half tones, and is commonly referred to as a “ghost” that is generated in the previous printing cycle. An example of a source of the positive charges is the stream of positive ions emitted from the transfer corotron. Since the paper sheets are situated between the transfer corotron and the photoconductor, the photoconductor is shielded from the positive ions from the paper sheets. In the areas between the paper sheets, the photoconductor is fully exposed, thus in this paper free zone the positive charges may enter the photoconductor. As a result, these charges cause a print defect or ghost in a half tone print if one switches to a larger paper format that covers the previous paper print free zone.
Excellent cyclic stability of the photoconductor refers, for example, to almost no or minimal change in a generated known photoinduced discharge curve (PIDC), especially no or minimal residual potential cycle up after a number of charge/discharge cycles of the photoconductor, for example about 100 kilocycles, or xerographic prints of, for example, from about 80 to about 100 kiloprints. Excellent color print stability refers, for example, to substantially no or minimal change in solid area density, especially in 60 percent halftone prints, and no or minimal random color variability from print to print after a number of xerographic prints, for example 50 kiloprints.
Also included within the scope of the present disclosure are methods of imaging and printing with the photoconductor devices illustrated herein. These methods generally involve the formation of an electrostatic latent image on the imaging member, followed by developing the image with a toner composition comprised, for example, of thermoplastic resin, colorant, such as pigment, charge additive, and surface additive, reference U.S. Pat. Nos. 4,560,635; 4,298,697 and 4,338,390, the disclosures of each of these patents being totally incorporated herein by reference, subsequently transferring the toner image to a suitable image receiving substrate, and permanently affixing the image thereto. In those environments wherein the photoconductor is to be used in a printing mode, the imaging method involves the same operation with the exception that exposure can be accomplished with a laser device or image bar. More specifically, the flexible photoconductor belts disclosed herein can be selected for the Xerox Corporation iGEN® machines that generate with some versions over 110 copies per minute. Processes of imaging, especially xerographic imaging and printing, including digital and/or color printing are thus encompassed by the present disclosure. The imaging members are, in embodiments, sensitive in the wavelength region of, for example, from about 400 to about 900 nanometers, and in particular from about 650 to about 850 nanometers, thus diode lasers can be selected as the light source. Moreover, the imaging members of this disclosure are useful in color xerographic applications, particularly high-speed, for example at least 100 copies per minute, color copying and printing processes.